Conventionally, as a power plant of this kind, there has been known one disclosed e.g. in Patent Literature 1. This conventional power plant is used for driving left and right output shafts of a vehicle, and is comprised of a first rotating electric machine and a second rotating electric machine as motive power sources, double pinion gears each integrally including a first pinion gear and a second pinion gear, a carrier rotatably supporting the double pinion gears, a first sun gear in mesh with the first pinion gears, a second sun gear in mesh with the second pinion gears, and a ring gear. The ring gear, carrier, first and second sun gears are in a collinear relationship in which the rotational speeds thereof are located on the same straight line in a collinear chart and are arranged from the left side in this order.
Further, in this conventional power plant, in order to transmit the torque difference between the first and second rotating electric machines to left and right drive wheels in an increased state, a connection relationship between the four rotary elements consisting of the ring gear, the carrier, and the first and second sun gears, the left and right output shafts, and the first and second rotating electric machines is set as follows: Out of the four rotary elements, two rotary elements positioned at respective outer locations in the collinear chart, that is, the ring gear and the second sun gear are connected to the first and second rotating electric machines, respectively. Further, two rotary elements positioned at inner locations in the collinear chart, that is, the carrier member and the first sun gear are connected to the left and right output shafts, respectively.